A buried layer of hoar frost most likely caused the accident on Sunday that took the life of Kirk Kinzer, Jr., according to the Payette Avalanche Center.

Kinzer, 20, of Lewiston, was snowmobiling with a group of people above Twin Lakes on Granite Mountain in the Payette National Forest backcountry when the avalanche hit him.

According to the Payette Avalanche Center website, investigators believe Kinzer’s snowmobile may have broken through a thin patch on the buried ice layer, triggering the slide on top of it. Such buried layers are responsible for the majority of avalanche accidents and deaths, according to the site. Investigators believe the hoar layer responsible for Sunday’s accident was buried just over 2 feet below the surface.

Investigators advise snowmobilers, skiers and others to take time to check for buried surface hoar on slopes before crossing any terrain steep enough for a slide. If they’re unsure, they should stay on slopes less than 30 degrees.